When the last run from a paragraph is underlined, the associated bullet has underline applied as well. The same applies for the background color.

When importing from HTML, all successive spaces in a spans are trimmed. Instead, in some cases one space should be left, e.g. between words. For example, the importing the following HTML should leave one space after the hyperlink:

<p><a href="www.telerik.com" target="_blank"><span>test</span></a>      and more.</p>

Workaround: After importing, check if the runs after the hyperlinks start with space:
foreach (var hyperlinkEnd in this.document.EnumerateChildrenOfType<FieldCharacter>().Where(f => f.FieldCharacterType == FieldCharacterType.End))
{
    Paragraph currentParagraph = hyperlinkEnd.Paragraph;
    int indexOfNextRun = currentParagraph.Inlines.IndexOf(hyperlinkEnd) + 1;
    if (currentParagraph.Inlines.Count > indexOfNextRun)
    {
        Run run = currentParagraph.Inlines[indexOfNextRun] as Run;
        if (run != null && run.Text[0] != ' ')
        {
            run.Text = " " + run.Text;
        }
    }
}

If HTML document is imported, and it contains image with invalid URL, then the image is imported with this URL in the document model. On subsequent export to Docx, the library tries to download the image data, which throws WebException. Instead, the image should be replaced with generic 'error' image.

Workaround: Manually test the image URL for correctness on HTML import, and replace the data:

        static void Main(string[] args)
        {
            HtmlFormatProvider htmlFormatProvider = new HtmlFormatProvider();
            htmlFormatProvider.ImportSettings.LoadFromUri += (sender, e) =>
            {
                if (!IsValid(e.Uri))
                {
                    e.SetData(File.ReadAllBytes("no-image.png"));
                }
            };
        }

        private static bool IsValid(string uri)
        {
            try
            {
                using (WebClient client = new WebClient())
                {
                    client.DownloadData(uri);
                }
            }
            catch (WebException)
            {
                return false;
            }

            return true;
        }

The empty lines are not converted properly from RTF to HTML

Workaround: 

Special chars (åäö) with PdfFormatProvider wont work.

Project submitted!

    public void SpecialCharsTest()
        {
            RadFlowDocument document = new RadFlowDocument();

            RadFlowDocumentEditor editor = new RadFlowDocumentEditor(document);

            editor.InsertText("Before text");
            editor.InsertText("åäö ÅÄÖ ☕"); // This line will not appear in the pdf 
            editor.InsertText("After text");
            using (Stream output = new FileStream("specialCharTest.pdf", FileMode.OpenOrCreate))
            {
                PdfFormatProvider provider = new PdfFormatProvider();
                provider.Export(document, output);
            }
        }

Special characters wont work :-/

When applying a table or table cell border with no thickness specified, the border is exported with a default thickness value of zero. However, by specification, the default value should be 2.

Workaround: Create a border by specifying the thickness value. For example:

table.Borders = new TableBorders(new Border(thickness, BorderStyle.Single, new ThemableColor(Colors.Black)));

In WordsProcessing on import only the lower case CSS attributes are correctly imported. Upper case and mixed case are ignored and the default values are used.